//
// Created by Asus on 2025/6/2.
//

#include <iostream>
#include <vector>
#include <bits/ostream.tcc>
using namespace std;

void demo01() {
    vector<vector<int>> v;
    vector<int> v1;
    vector<int> v2;
    vector<int> v3;
    vector<int> v4;

    for (int i = 0; i < 4; i++) {
        v1.push_back(i+1);
        v2.push_back(i+2);
        v3.push_back(i+3);
        v4.push_back(i+4);
    }

    v.push_back(v1);
    v.push_back(v2);
    v.push_back(v3);
    v.push_back(v4);

    for (vector<vector<int>>::iterator it = v.begin(); it != v.end(); it++) {
        for (vector<int>::iterator it2 = it->begin(); it2 != it->end(); it2++) {
            cout << *it2 << endl;
        }
    }
}

int main(int argc, char *argv[]) {
    demo01();
    return 0;
}
